The aim of this study was to evaluate the pollen viability and longevity of Cannabis sativa, which is a significant economic crop. Viability and longevity are evaluated using different staining techniques: Alexander's, Triphenyl Tetrazolium Chloride (TCT) and Fluorochromatic Reaction (FCR). The results of this study show that FCR is the most reliable and accurate for assessing viability and longevity in C. sativa. Viability was measured over days and across 2010. Viability was greatest between 0 - 3 days of anther dehiscence and during April, whilst December had the lowest pollen viability. For Cannabis sativa the first 3 days after anthesis are the most important for fertilization, following the 3rd day there is a rapid decline in viability.